Sinistral and dextral are the two types of relative direction.
If the opening is on the left then the shell (Limnaea peregra) is left-handed, or 'sinistral'.
In most snails, shells are dextral .
dextral : on the right side or the right hand.
One of the classical examples of detailed relationship between maternal genotype and egg cytoplasm “phenotype” was studied in snails .
Looking into the opening of the shell it can be seen that in one strain the shell always coils to the left (sinistral) whereas in the other shell always coils to the right (dextral).
In the cross dextral (female) x sinistral (male) all the F, progeny have dextial coils that implies dextral is dominant over sinistral. However, in the F1 x F1 cross (i.e., inbreeding) all the F1 snails are also dextral. The reciprocal cross ( dextral (female)x sinistral (male)) produces F1 progeny that are all left coiler. In this case F1 x F1 cross also yields only dextral coils.
it is clear that coiling of snails is not determined by individuals own genes but by those of mother. The coiling is phenotype in the offspring is controlled by the genotype of the mother.
In simple words ,
when dextral female is crossed to a sinistral male : the result will be all dextral.
when sinistral female is crossed to a dextral male :the result will be all sinistral.
Answer:
Due to absence of strong winds and its costly machines.
Explanation:
Wind power is not being used all across the world because strong winds are not present in every region of the world. Strong winds are needed to move wind turbines for the production of electricity. The instruments and machines that are necessary for electricity production from wind are very costly and not everyone has the capability to install it so that's why it is not being used all over the world.
Sampling
- counting the number of organisms in a small area and multiplying to estimate the number in a larger area
Mark & Recapture
- capture an organism & release it to remix with population. Then recapture some more in that area to determine population size. Formula is as follows: R (marked recaptures) / C (total in second sample) = M (marked initially) / N (total pop. size)
Indirect Observation -
estimating the population size by tracks, nest or other animal signs in an ecosystem.
It goes into the ground, then evaporated, where the air sorta cleans it, and then it gets rained back down
